Callan is making pizza using flour, tomatoes, and mozzarella cheese. This table gives the cost, per kilogram, of each ingredient, and the amount, in kilograms, that Callan uses: Ingredient Price per kilogram Amount Flour $0.80$ dollars per kilogram $x$ kilograms Tomatoes $3.30$ dollars per kilogram $y$ kilograms Mozzarella $z$ dollars per kilogram $0.5$ kilograms The total amount Callan spends on ingredients is $C$ dollars. Write an equation that relates $x$, $y$, $z$, and $C$.
Explanation: Let's find the amount of money Callan spends on each ingredient. Then we can add all these up to find the total sum. For example, flour costs $0.80$ dollars per kilogram and Callan uses $x$ kilograms of it, so Callan spends $0.8x$ dollars on flour: $\begin{aligned} &\phantom{=}\left(0.80\,\dfrac{\text{dollars}}{\text{kilogram}}\right)\left(x\,\text{kilograms}\right) \\\\ &=0.8x\,\dfrac{\text{dollars}}{\cancel\text{kilogram}}\cdot\,\cancel\text{kilograms} \\\\ &=0.8x\,\text{dollars} \end{aligned}$ Similarly, Callan spends $3.3y$ dollars on tomatoes and $0.5z$ dollars on mozzarella. Ingredient Price per kilogram Amount ${\text{Price}}$ Flour $0.80$ dollars per kilogram $x$ kilograms ${0.8x\text{ dollars}}$ Tomatoes $3.30$ dollars per kilogram $y$ kilograms ${3.3y\text{ dollars}}$ Mozzarella $z$ dollars per kilogram $0.5$ kilograms ${0.5z\text{ dollars}}$ The total amount Callan spends on ingredients is the sum of the prices of each ingredient: $C=0.8x+3.3y+0.5z$